The present invention generally relates to aircraft armament apparatus and, in a preferred embodiment thereof, more particularly relates to the external mounting of armament apparatus on a helicopter.
The xe2x80x9cBlackhawkxe2x80x9d military helicopter has a cabin area positioned behind the cockpit area and having sliding gunner""s windows on opposite sides thereof. Using conventional mounting techniques, either 7.62 mm mini-guns or single barrel 7.62 mm machine guns may be mounted on the horizontal sill areas of these gunner""s windows on articulated support linkage assemblies that permit the guns to be swung outwardly through the opened windows to use orientations, or inwardly through the opened windows to storage orientations. Various well-known problems, limitations and disadvantages are associated with this conventional helicopter armament mounting technique.
For example, with both the 7.62 mm mini-guns and the single barrel 7.62 mm machine gun, the articulated, sill-mounted support structure for the gun has an undesirable amount of positional xe2x80x9cplayxe2x80x9d therein which, although necessary for gun adjustment and deployment, substantially degrades the firing accuracy of the gun. Additionally, while-the single barrel 7.62 mm machine gun has an ammo box mounted directly on the gun, the 7.62 mm mini-gun has an external ammo box that must be positioned in the adjacent cabin area, with the belted ammunition fed from the ammo box, out the gunner""s window and to the gun. This, of course, undesirably clutters up the cabin area. Another problem associated with this sill mounting of both the 7.62 mm mini-gun and the 7.62 mm single barrel machine gun is that the gunner""s windows cannot be closed with the guns in their ready positions. This inability to close these windows leads to uncomfortably cold cabin temperatures during cold weather missions, and fuel mist potentially entering the cabin area during in-flight refueling.
With either the 7.62 mm mini-gun or the 7.62 mm single barrel machine conventionally mounted on a cabin area gunner""s window sill, the maximum upward firing angle of the gun relative to horizontal is approximately 1.5 degrees. This is due to the fact that, with the sill-mounted gun pointed forwardly along a side of the helicopter, this is the maximum upward firing elevation angle of the gun that (with a pre-determined margin of safety) will position its bullet path safely beneath the helicopter""s forwardly drooped rotor blade tip path to preclude bullet impact with the spinning rotor blades. This 1.5 degree maximum upward elevational firing angle of the gun undesirably limits the maximum firing range of the gun when the gun is swung away from its forwardly pointed orientation xe2x80x94for example when it is being fired off to the side of the helicopter or to the rear thereof.
Yet another limitation presented by this conventional helicopter window sill-mounting of machine guns is that larger machine guns, such as to 0.50 caliber machine guns, are difficult to deploy, and, because of their weight, intensify crash load issues.
These problems, limitations and disadvantages associated with conventional gunner""s window sill mounting of machine guns were addressed by the present applicant""s helicopter sponson tow plate-mounted armament apparatus illustrated in his U.S. Pat. No. 6,250,197, the disclosure of which is hereby incorporated by reference herein in its entirety. In such armament apparatus, a machine gun, ammo box and flare dispenser are externally mounted, adjacent a gunner""s window, on a specially designed landing gear sponson replacement tow plate. The external machine gun mounting permitted by this specially designed system frees up cabin space, permit""s the gunner""s window to be closed with the gun in a ready position, and permits a 0.50 caliber machine gun to be used as an alternative to either a 7.62 mm mini-gun or a single barrel 7.62 mm machine gun adjacent the gunner window.
While the tow plate-mounted helicopter armament apparatus illustrated and described in U.S. Pat. No. 6,250,197 provides the advantages set forth above, it has been found in the development of the system that it would be desirable to provide it with various modifications and improvements to the design xe2x80x94such as improved positioning of its components, the provision of additional external armament, cost reduction, enhanced positional control of the machine gun, and maintenance and installation simplification xe2x80x94would be desirable. It is to these improvements in the design of the sponson tow plate-mounted external helicopter armament apparatus illustrated and described in U.S. Pat. No. 6,250,197 that the present invention is primarily directed.
In carrying out principles of the present invention, in accordance with a preferred embodiment thereof, specially designed external armament apparatus is secured to an aircraft landing gear structure, representatively a landing gear sponson tow plate of a helicopter. Although various components of the armament apparatus may be deleted, and various component combinations may be utilized depending on the helicopter""s mission, in a representatively complete form thereof the external armament apparatus illustratively comprises:
1. A pintle arm assembly secured to and projecting upwardly from a central outboard side portion of the tow plate;
2. A yoke assembly secured to an upper end portion of the pintle arm assembly for horizontal pivoting relative thereto;
3. A cradle assembly secured to the yoke assembly for horizontal pivoting therewith and vertical pivoting relative thereto;
4. A machine gun, representatively a .50 caliber machine gun, operatively carried by the cradle assembly;
5. An ammunition box/booster assembly mounted on a top side edge portion of the tow plate, inboard of the pintle arm assembly, and adapted to hold a length of belted ammunition feedable to the machine gun;
6. A flare dispenser mounted on a rear end portion of the tow plate and positioned generally beneath the pivot area of the machine gun;
7. An external stores assembly including a support structure secured to the outboard side of a lower end portion of the pintle arm assembly and external stores apparatus, representatively a missile launcher, operatively mounted on the support structure; and
8. A forward-looking infrared (FLIR) sensor secured to a front end portion of the tow plate.
The machine gun, which may be of various types, including, for example, a 0.50 caliber gun, a 7.62 mm mini-gun, or a single barrel 7.62 mm machine gun, is operatively supported outside a gunner""s window to thereby permit the window to be closed when the gun is not being used, and the external positioning of the ammunition box reduces clutter in the cabin area of the helicopter. The positioning of the flare dispenser beneath the pivot area of the machine gun prevents potential interference between the flare dispenser and the gun barrel/projectile path when the gun is being pivoted in a depressed elevational orientation.
In one illustrative embodiment thereof, the pintle arm assembly includes a pintle block member secured to a central outboard side portion of the tow plate and has an opening extending therethrough along an upwardly and rearwardly inclined axis. An elongated, substantially straight support arm member extends along a longitudinal axis and has a lower end portion coaxially locked within the pintle block opening by a transverse retaining pin structure. The lower end of the support arm has a conically tapered annular outer side surface portion which engages a similarly tapered interior surface portion of the pintle block opening. A tapered annular collet member is forced against a second conically tapered annular interior surface area of the pintle block opening by a nut tightened onto a threaded lower end of the support arm.
In an alternate embodiment of the pintle arm assembly, the support arm has a uniform cross-section along its length and is captively retained within the pintle block opening by a pair of expansion pins extending transversely through the pintle block and the lower end of the support arm.
The machine gun, and its associated cradle and yoke assemblies, are mounted on the rearwardly and upwardly offset upper end of the installed support arm for azimuth and elevation rotation relative to the pintle arm assembly respectively about vertical and horizontal axes, the vertical axis representatively being forwardly and upwardly inclined relative to a vertical reference axis at a small angle which is preferably about three degrees to match the rotor system forward tilt.
According to another feature of the invention, a specially designed elevation limiting system may be associated with the machine gun, when the external stores assembly is included in the overall external armament apparatus, and serves to prevent the gun""s bullet path from intersecting a front portion of the installed missile launcher assembly when the gun is in a forward portion of its azimuth arc. The elevation limiting system functions, in response to horizontal azimuth rotation of the gun, to automatically provide a downward gun rotation limit angle which, with the gun in a predetermined forward portion of its azimuth arc, is less than the downward gun rotation limit angle when the gun is in a predetermined rearward portion of its azimuth arc.
In a preferred embodiment thereof, the elevation limiting system includes a cam follower/stop member carried for variable driven rotation parallel to the gun""s vertical azimuth rotation axis and functioning to variably block downward rotation of the gun cradle portion in forward and rearward gun azimuth travel arcs.
In accordance with another aspect of the invention, a portion of the machine gun is removably secured to the cradle structure using an annular trunnion nut member secured to the gun and positioned between two support block portions of the cradle. A diametrically opposite pair of radial openings extending through the trunnion nut are aligned with horizontal openings extending through the support blocks. To releasably lock the trunnion nut to the support blocks, a pair of specially configured nonthreaded locking studs are provided and are inserted inwardly through the support block openings so that nonthreaded inner end portions of the studs are received in the opposed trunnion nut openings. The inserted studs are releasably locked in place within the horizontal support block openings by suitable retaining pins extending downwardly through upper end openings in the support blocks and having lower end portions received in transverse openings in the inserted studs.
According to another feature of the invention, the external stores assembly includes an external stores support structure anchored to the pintle support block and projecting in an outboard direction from the tow plate, and provided with adjustment structure permitting the external stores apparatus which it carries to be pivotally adjusted about at least one axis relative to the support structure. Representatively, this adjustment structure provides for elevational adjustment of the external stores apparatus and includes front and rear elevation adjustment bolts that bear against, and may be variably adjusted relative to, portions of the supported external stores apparatus. As used herein, the term xe2x80x9cexternal storesxe2x80x9d encompasses armament apparatus, such as missiles, rockets and rocket launchers, additional guns, electronics, etc. which are carried externally to the aircraft and are typically, though not necessarily, jettisonable.
In accordance with another aspect of the invention, the forward-looking infrared sensor is secured to a front end portion of the tow plate in a manner positioning the sensor in a forwardly spaced apart relationship with the tow plate. This positioning is representatively achieved using a mounting structure including a rear block portion secured to a front edge portion of the tow plate, an elongated mounting member longitudinally projecting forwardly from the rear block portion and having a front end, and a front block portion secured to the front mounting member end and overlying and being secured to a top end portion of the sensor.
The feed booster portion of the ammunition box/booster assembly includes a booster housing having disposed therein a sprocketed electric drive motor operable to engage an ammunition belt disposed in the ammunition box and drive it outwardly therefrom for delivery to the machine gun during firing thereof. According to yet another aspect of the invention, the drive motor is mounted in a removable booster housing portion of the ammunition box/booster assembly in a unique manner permitting the motor to be operatively installed in and removed from the booster housing without the use of tools of any sort.
Representatively, the motor is provided with opposite mounting end portions through which locking openings extend. The motor is inserted into the booster housing, through an access opening therein, in a manner positioning the motor end locking openings between facing exterior and interior mounting opening sets formed in the booster housing. Removable pin members are inserted through the aligned housing motor openings to captively retain and operatively position the motor within the booster housing. By simply removing the booster housing from the ammunition box and removing these pins, the motor can be removed from the booster housing without the use of tools, and a replacement motor can be positioned in the removed booster housing similarly without the use of tools.